An electronics device may include a microcontroller unit (MCU) that may be used to perform a number of different applications. The MCU may include a processor core that, for example, processes incoming and outgoing streams of data for the electronic device. As a more specific example, in a mobile telecommunications device, the processor core may process data that is communicated over a wireless network.
For purposes of communicating with its peripherals, processing data and so forth, the processor core may operate in an active mode in which the processor core consumes a relatively large amount of power. For purposes of conserving power when the processor core is relatively inactive, the processor core may transition into a lower power consumption state.